Be it known that I, WILLIAM W. HUBBELL, of the city of Philadelphia and
State of Pennsylvania, now attorney at law, have invented a new and useful
Improvement in Elongated Explosive Shells, to fire from cannon, howitzers,
and guns of large caliber; and I do here-by declare that the following is
a full, clear, and exact description thereof, reference being had to the
accompanying drawings, making part hereof.

The nature of my invention consists in the formation and arrangement of
metal of the elongated explosive shell, to be hereinafter described,
consisting of the following combined essential conditions: First, the back
part of the shell must be a smooth semi-spherical surface, and the
thickness of its metal uniform, as near as may be, to give the greatest
strength and powder space with the least proportional weight, and for
other reasons that will be presently described in their relation to the
other parts; second, the body of the shell in front of this semi-spherical
hinder part must be cylindrical, and the thickness of its metal (excepting
the head to be presently described) the same or a little greater than the
thickness of metal of the hinder part, to give the greatest possible
proportional powder-space, and for other reasons also to be presently
stated, in the combination or relation to the other parts; third, the head
or front part of this cylindrical surface or body is through the fuze-hole
at least twice as thick in metal as the thickness of the semi-spherical
hinder part, for the same reasons set forth in the specification of my
patent for an improvement in eccentric explosive shells, dated 22d of
January, 1856; and on the front face of the head of this shell the metal
composing the head is formed in a series of oblique or propeller surfaces
radiating from the fuze-hole, which passes through the center of the head
parallel with the cylindrical surface of the body, to properly give the
shell a rotary motion. It should be particularly observed, and I specify,
that the smooth semi-spherical hinder part has no ears, tails, or wings
thereon, but is smooth, because (as I have discovered by experiment) the
air, being less dense behind than in front of the shell in its flight, is
least liable to act on the wings when behind, and also, particularly,
because the weight of metal of such wings or tails, when behind, by its
momentum tends to counteract both the action of the air on their surfaces
and the necessary predominance of the weight of the head or front part,
and thus, and also from the action of crosswinds on their surfaces,
disturb the true flights of the shell, the same being also explained in my
aforesaid patent of 22d January. The back of the shell, therefore, must be
a smooth semi-spherical surface. Also, to prevent error, I particularly
specify that the body of this elongated shell must not consist of or have
on the windage surface, or part nearest the metal of the gun, any
spirally-formed wings extending both before and behind the center of
gravity longitudinally, because the momentum of the metal of the portion
of the wings behind the center of gravity of the mass tends to counteract
the momentum of the metal of the portion of the wings before the center of
gravity, as well as the action of the atmosphere on such hinder surfaces
of the wings, and thus destroy the necessary predominance of momentum of
the metal in front, and also because the open space between the spiral
longitudinal wings, when the shell is in the gun, allows the power of the
exploding cartridge to escape from behind the shell too much through the
openings between the wings, while it is most needed to give projectile
force to the shell out of the gun, and because such spiral longitudinal
wings diminish the powder-space in the shell.

The body or barrel of the shell, between the head and the hinder part,
must be a smooth cylindrical surface of, as near as may be, uniform
thickness, and have only the usual windage in the gun.

The head or front part of this shell is peculiar, in combination with
the cylindrical barrel or body and semi-spherical back or hinder part, in
order harmoniously to give the shell a proper rotary motion, such as is
given to a rifle-ball by the grooves in the barrel of the rifle, to attain
a truer flight.

It is a great object in this invention to have the metal that forms the
oblique or propeller and as far forward of the center of gravity of the
body or shell as possible, in order to have the same metal that forms the
propeller-surfaces and gives the rotation also give the assistance of its
weight, to cause the greatest predominance of momentum possible, to keep
the head, propellers, and fuze in front.

The object in keeping the propellers in front is to have their surfaces
exposed to the most dense air in the flight of the shell, (it being of
course most dense in front,) to obtain the best effect, to cause the
rotation of the shell on an axis coincident with its true line of flight;
also, to have the metal forming them add their momentum most effectively
to that of the head by forming a part thereof, instead of detracting from
it, and thereby give the shell, though of elongated form, a most true
flight, and the fuze, being in front, acts most effectively, for reasons
given in said patent of 22d January, the object of this invention, as
differing from that described in that patent, being to obtain a much
larger shell for any given size of gun, capable of carrying more powder
and of exhibiting more explosive force and destructive effect, and yet
have it of such form and arrangement of metal as to correct the
difficulties that have existed in the flight and form of elongated shells
before my invention. Therefore the head of this shell, to attain these
results, must be at least twice as thick through the fuze-hole as at the
back part; must have the propeller-surfaces formed by the metal of the
head itself on the front face of the cylindrical body as far forward of
the center of gravity of the entire mass as possible, and uniformly around
the fuze-hole, with the back part a smooth semi-spherical surface.

Reference being had to the accompanying drawings, Figure 1 is a side
view of the external surface or form. Fig. 2 is a sectional view through
the center of the head, fuze-hole, and body of the shell; and Fig. 3 is an
outside view of the front or head of the shell, showing its oblique faces
and fuze-hole, in all of which figures like letters refer to like parts.

A is the hollow of the shell, to contain the explosive powder, having
the cylindrical barrel or body.

B is the thickness of the metal of the hinder portion of the shell,
being uniform in thickness, excepting the slight variation often caused by
the rising of the core in casting, and being semi-spherical in form.

C is the fuze-hole, with the metal of the head at least twice as thick
through it as the thickness of the metal of the hinder part of the shell,
and this head has the four front oblique surfaces D D D D uniformly
combined around the fuze-hole on the extreme front face of the cylindrical
body, making the head much greater in mass or weight than the hinder part
of the shell, and giving the shell in its flight a rotary motion on an
axis coincident with the line of flight. The tendencies, therefore, to
keep the fuze foremost and make the shell fly true are the rotary motion
of the shell on its axis and the predominant momentum arising from the
form and amount of this head with the fuze-hole through its middle.

The faces of the oblique surfaces may be made straight instead of
curved, and of various angles of obliquity, without materially changing
the principle; but the curved faces and angle given in the drawings embody
a large predominance of mass in the head, and also give sufficient angle
and surface to cause the necessary rotation of the shell.

The shell is loaded in the gun with the semi-spherical hind part next
to the cartridge, and its length may be varied; but about two and a half
diameters of the bore of the gun for the length is recommended as giving
great effect for short ranges; and if a very long range is desired, two
diameters may be used for length.

Any of the fuzes and the ordinary windage may be used, and to
facilitate the firing of the fuze in this shell of large diameter and long
cylindrical windage, a small groove should be made extending each way on
opposite sides from the fuze along the bases of opposite oblique faces to
the windage, filled with gun-powder and covered with a lead plate or rib
set in a dovetail groove on top of the train, the ends near the windage
and fuze being perforated, and covered with tinsel to break and fire, and
thus form a train to ignite the fuze from the cartridge, and yet before
use be protected by the lead rib and tinsel from the weather and
accidental fire.

I do not claim spirally-winged elongated shells, nor elongated shells
with cylindrical body and spherical hinder part either with or without
tails or wings behind, nor with enlarged head, for I am aware that they
have been long known, and I have many years ago experimented with them.

What I claim is -

Combining or forming a series of oblique or propeller surfaces
uniformly around the fuze-hole, on the extreme front face of the metal of
an enlarged or thickened head of an elongated shell, with cylindrical body
and smooth semi-spherical hinder part, substantially as described.